The present invention relates to a washing machine for the washing of fabrics such as clothes and, more particularly, to a washing machine of the vertical-axis type wherein a single basket receives both the items being washed and the washing liquid.
Conventional clothes washing machines of the vertical-axis agitator type are traditionally rather large and complex. In such machines, generally there is provided a cabinet enclosing an outer water-retaining tub in which is situated an inner, clothes-receiving basket. An agitator is mounted within the inner basket. The agitator and the basket are coupled to a suitable power transmission driven by an electric motor. The transmission converts the high speed revolutions of the motor to the speed appropriate for centrifugal extraction of water and to the oscillatory motion appropriate for agitator movement during the wash cycle. Such machines generally include a water pump for recirculating water within the machine and a filter for separating out lint and other particles from the recirculated water. Included with the pump and filter mechanism is a plethora of plumbing and hoses. Inherently, such machines use large amounts of water. Also, there is a high energy interface between the clothes being washed and the oscillating agitator, causing high wear of fabrics being washed. Many machines also suffer from vibration and travelling problems resulting from unbalances in the machines during the centrifugal water extraction or spinning operation. Other machines use complex suspension systems including counterweights, and many times the clothes basket is also provided with an annular balance ring disposed somewhere around the circumference thereof to alleviate this problem.
Attempts have been made to simplify these washing machines, and especially the drive mechanisms thereof, and the "wobble" type of machine is one such effort. U.S. Pat. No. 2,555,400 to De Remer discloses a wobble type of washing machine including a non-rotating tilted spin shaft which rests against inverted conical walls of a gyrator and is moved in a conical path so that the axis of the basket describes a cone having an apex below the basket. Helical blades on the basket wall provide a vortex motion to the clothes and motion about the rotor axis in a direction opposite to movement of water and direction of gyration. A spring centering force and gyroscopic forces cause the spin shaft axis to move to a vertical position for the spin mode of operation. Many other wobble-type machines are known such as the machine shown in U.S. Pat. No. 2,549,824 to Kost, where the tub axis is made to wobble in a conical path while the tub is oscillated about its own axis. The washing motion is accomplished by an inclined post and a ball pivot, extended into a cocked off-center bearing in a worm wheel. An attached slide link provides angular placement of the post about its axis. Most of the wobble-type of washing machines share the problem of expensive complex suspension systems and such designs place very large stresses on the systems.
U.S. Pat. No. 2,432,766 to Kirby describes a washing machine wherein the clothes-receiving receptacle is caused to execute an orbital movement while at the same time being rotated about its own axis. The motion is achieved by the provision of a nested assembly of interfitting sleeves within which a drive shaft is eccentrically mounted. Rotation of the shaft causes rotation of the basket about its own axis. Although the degree of gyration appears to be much less than in a true wobble-type washer, the motion is still of the nutating or wobble type.
Other washing machines are also known in which the wash basket is oscillated, such as U.S. Pat. No. 3,738,130 in which an oscillatable basket is provided within a washing machine tub. A pair of blades are attached eccentrically to the basket for affecting a washing action. A more dated means of obtaining washing action in a vertical-axis type of machine wherein basket motion rather than agitator motion provides the washing forces is shown, for example, in U.S. Pat. No. 1,688,555 to Rankin wherein two or more clothes chambers revolve around the center of an outer water chamber, at the same time revolving on their own axis.
It is desirable then to provide a washing machine of the vertical-axis type having a relatively simple and uncomplicated drive mechanism and effective to move the wash basket so that the predominant energy transfer to the load being washed is through the basket sidewall, and without requiring expensive and complex vibration dampening and counterbalancing structure. It is also desirable to provide a washing machine wherein the mass of the suspended tub and drive components are used to advantage in both the wash and spin modes of operation. It is also desirable to provide a relatively simple and low-cost drive train or transmission; to provide a washing machine basket which may use common wash and spin speeds and which has the ability to handle large or small loads gently with minimum wear to the fabrics; and to provide a machine which has low water usage. It is also desirable to provide a washing machine in which the energy input to the fabric articles being washed is an approximate function of the load size. It is further desirable to provide a washing machine which has an effective detergent concentration level with minimum total detergent use, which has few parts and low component stress levels, which is reliable, which uses a symmetrical rotating mechanism and which has a wash basket which provides excellent clothes turnover and washability. It also is desirable to provide a flow-through wash system which continuously washes with fresh water and continuously flushes water, with its entrained lint, scum and soil, down the drain.
The present invention provides a washing machine of the vertical axis type which is rather simple of construction, highly reliable, and of economic construction and which meets one or more of the requirements above described and other objectives.